Briefly, there is a need for improved toners that can be charged either positively or negatively for use in office copiers and laser printers. The improvements sought are in the areas of improved flow and wetting, lower energy for fusing, ability to deink toners from office waste paper, and toner resins that are derived from renewable resources. The ability of the resin to inherently provide negative charging to tone positively charged latent electrostatic images is of greater interest as a significant share of the copier and printer market use such toning systems. Conventional toners are based on synthetic resins such as styrene acrylates, polyesters, polyamides, etc. Resins derived from renewable resource feedstocks such as corn, soybeans and other plants are gaining wider interest due to environmental sustainability long term supply concerns with petroleum-derived resins. Examples of bio-based resins are derived from dimer acid and D-isosorbide that have good toning and printing features like the current petroleum resin-based toners.
There is also a need for toners incorporating resins with the ability to disperse pigments. Bio-based polyester resins derived from dimer acid and D-isosorbide, used in powder coating formulations, gave a final coating with improved pigment dispersion. There is also a need for resins that flow at lower fusing temperature to minimize the energy consumption to operate a copier.
There is a great deal of interest in the replacement of some petrochemical feedstocks with bio-based feedstocks for use in a wide range of application areas. Evidence of this interest is reflected in the number of review articles that have been published through the years. Efforts to utilize bio-based feedstock in the synthesis of polyester resins are exemplified in U.S. Pat. No. 6,063,464, wherein corn bio-mass derived isosorbide is used in the synthesis of polyester materials.
Related art includes U.S. Pat. No. 5,959,066; U.S. Pat. No. 6,025,061; U.S. Pat. No. 6,063,464; and U.S. Pat. No. 6,107,447.